Several days ago I was greeted during my breakfast by this bird roosting in the ginko tree in our yard. It's a red-tailed hawk, the most common hawk in North America. Their range extends over nearly the entire continent except the very northernmost part and into Central America and Jamaica (hence the species name). There are three distinct "morphs" or forms and a total of fourteen subspecies with fairly different color patterns, most of which lack the distinctive red tail, which can make identification between this bird and some of the other common North American hawks a little tricky. However, because they are so common, if you see a hawk in North America it is very likely to be a red tailed hawk.
These birds of prey prefer areas where they can roost fairly high and watch over a wide flat area for prey. In New England they feed mostly on mammals such as rabbits, squirrels and mice. In the desert parts of the continent they feed mostly on snakes. To protect themselves from bites the red tailed hawk has a thick scale covering on its legs. After landing on the snake it will pin the prey item's head as quickly as possible to prevent retaliation.
Usually you can see these birds in flight, circling in the air watching for prey. I also hear their calls a fair amount even in the city.
Frances, Peter (senior editor) (2007) Bird. DK Publishing: New York, New York.
National Geographic: http://animals.nationalgeographic.com/animals/birds/red-tailed-hawk/
Cornel Lab of Ornithology: http://www.allaboutbirds.org/guide/Red-tailed_Hawk/id